Highway crossing gate



NOV. 26, 1940. E 2,223,218

HIGHWAY CROSSING GATE Original Filed Oct. 5, 1938' mum M INVENTOR Edw' Gliztb. BY

HIS. ATTORN EY Patented Nov. 26, 1940 The Union Switch & Signal Cbmpany,"Swiss vale, Pa., a corporation of Pennsylvania.

Original application October 193 8, Serial No. 233,437. Divided and this application August 29, 1939, Serial No. 292,430

"2 Claims.

My invention relates to highway cros in gates.

One object of my invention is to provide a highway crossing gate of the type having a 5 counterweighted gate arm biased to a lowered position and arranged to be moved to a raised or non-traffic obstructing position by a motor driven operating mechanism, in which the gate arm counterweight will be prevented from dropping suddenly and thereby causing damage to the operating mechanism, in the event that the gate arm becomes broken while it is in its lowered or traffic obstructing position.

Other objects and characteristic features of my invention will appear as the description proceeds.

The present application is a division of my copending application, Serial No. 233,437, filed on October 5, 1938 for Flexible coupling.

I shall describe one form of highway crossing gate embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawing, Figs. 1 and 2 are front elevational and top planviews, respectively, showing a highway crossing gate embodying my invention. Fig. 3 is an enlarged vertical sectional view of a coupling which is utilized for connecting the gate arm with the associated operating mechanism. Fig. 4 is a sectional view taken substantially on the line IV-IV of Fig. 3. Fig. 5 is a view showing the coupling member l2 in place on the shaft In,

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1 and 2, the reference character I designates a highway crossing gate arm, and the reference character 2 designates a mechanism for operating the gate arm I. The gate arm I is of the type which is adapted to descend by gravity to its lowered or traffic obstructing position, and to be subsequently moved to its raised or non-trafic obstructing position by means of the operating mechanism, and as here illustrated it is secured to the outer end of an 45 operating shaft 3 journaled in suitable bearings 4 mounted in a supporting bracket 5. The

bracket 5, in turn, is secured in any suitable manner as by means of U-bolts 6 to a signal pole 50 .or mast 1, and is provided at the end opposite to the gate arm with a flange 8 to which the operating mechanism 2 is bolted. It will be seen, therefore, that the bracket 5 serves as a means for securing both the gate arm and the operating mechanism to the supporting pole I. To prevent the gate arm from developing excessive torque when it is descending, suitable counter-'- weights 3 are provided in accordance with the usual practice.

The operating" mechanism 2 may be of any preferred type which, when energizedfwill move the gate arm against its bias to its raised position and hold it there, but which when'deenergizedwill permit the gate arm to descend by gravity to its lowered position. As here shown, this mechanism is similar to that show'n'and described in Letters Patent of the United States No.1,138,087 granted to John P. Coleman on May 4-,, 1915, for a Railway signal, and inasmuch as this mechanism in itself forms no part of my present invention, and is described in detail in the said Coleman patent, it is believed to be s'uffi cient for purposes of the present disclosure to point out that this mechanism includes a main shaft H] which is disposed in axial alignment with the shaft 3, and which is connected with an electric motor not shown through suitable ratchet mechanism in such manner that when the motor is energized it will rotate the shaft ID in a counterclockwise direction as viewedfrom the right in Fig. 3 through a sufiicient angular distance to move the crossing arm from its lowered to its raised position, and that when the arm reaches its raised position the ratchet mechanism will permit the motor armature to coast to a stop without shock. This mechanism also includes an electromagnet' .which becomes energized when the motor becomes energized, and which is effective when energized tohold the shaft 10 in anyposition to which it is rotated by the motor, but which when deenergi'zed permits the shaft to rotate in the opposite direction from that which it is driven by the motor an to rotat theimo The echan u ther includes suitable circuit controlling contacts for deenergizing the motor when the crossing arm reaches its full raised position without deenergizing the electromagnet, and for shortcircuiting the motor to cause it to act as a brake when the motor is being driven by the descending gate arm.

The two shafts l0 and 3 are operatively connected to operatively connect the gate arm I with the operating mechanism 2 by means of a coupling which is disposed within a cylindrical opening I I formed in the rear wall of the operating mechanism 2. As shown in the drawing, the coupling comprises a main coupling member l2, a main coupling member I3 and two link members l4 and IS. The member I2 is provided projecting pins I31) and I30, and is secured to a the shaft 3 by means of a pin II. The squared ends of the shafts I and 3 are so arranged that when these shafts occupy the proper relative operating positions, the four pins I2b, I31), I20 and I30 will be disposed at the four corners of a rectangle in the order named, as shown in Fig. 4.

The link member I4 comprises a central web portion I ia provided with two cam slots [4b and I to which receive the .pins I21) and I30, respectively, of the two coupling members I2 and I3, and an arcuateouter portion 14d to vwhich a brakelining I8 of suitable friction material is fitted for cooperation withthe wall of the opening II. The link member I5 similarly comprises a central web portion I5c provided with two cam slots: I52) and I50 which receive the pins I20 and I3b, respectively, of the two coupling members I2 and I3, andan arcuate outer portion I 5d to which a brake lining I9 of suitable friction material is fitted for cooperation with the wall of the opening II.

The operation of the gate is as follows: The cam slots in the two link members are so constructed and the parts are so proportioned that when the shaft I0 is rotated by the operating mechanism in the proper direction to raise the gate arm I, or the shaft 3 is rotated in the direction it is rotated when the gate arm is descending by gravity, the pins I22), I31), I20 and I3c will each cooperate with the associated cam slot toforce the links inwardly to the positions in which the brake linings are out of engagement withthewall of the opening II, and it will be apparent, therefore, that when the motor is being operatedtoraise the gate arm, or the'g'ate arm is descending by gravity, the coupling will transmit torque directly from the one shaft to the other without any frictional force being exerted on either shaft due 'to the brake linings. If, however, a forcefis ap'plieddirectly to theshaft 3 tending to rotate the "shaft in the opposite direction fromthat in whichit is rotated to lower the gate armas will be the case if someone attempts to raise the gate arm by hand, or if a vehicle 001-- lideswith the gate when it is lowered and breaks I it off so that the' counterweights 9 tend to drop suddenly, the pins I21), I31), I2cand I3c will then cooperate with the associated cam slots to force the links' outwardly to the positions in which the brake. linings I8 and I9 frictionally engage the force applied directly thereto, or merely as a means for limiting the amount of force necessary to rotate this shaft, or as a means for limiting its rate of movement or both. In the latter case, the

. crossing gate arm could be raised by hand in an emergency, although the braking effort exerted by the coupling would still be sufiicient to retard the fall of the counterweight and thus prevent damage to the operating mechanism, in the event that a car ran into the gate arm and broke it oif. Although I have herein shown and described only one" form of crossing gate embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a signal arm biased to a lowered position and provided with a counterweight, an operating mechanism for moving said arm to a raised position, and a coupling connecting said arm with said mechanism and including means for preventing said counterweight from dropping in the event said arm becomes broken while'in its lowered position.

2. In combination, a supporting post, a bracket secured to said post, an operating mechanism secured to said bracket and provided in a wall adjacent to said bracket with a cylindrical opening and with a'shaft extending into said opening, a second shaft journaled in said bracket and having one end extending into said opening in axial alignment with said mechanism shaft, an arm secured to said second shaft and biased to a lowered position and partly counterbalanced by a counterweight, and a coupling disposed in said opening and including means for connecting said mechanism shaft with said second shaft in such manner that movement'of said arm to its lowered position will drive said mechanism shaft and that operation of said mechanism will move said arm to its raised position but that rotation of said second shaft in a direction to move said arm to its raised position by means other than said mechanism is prevented.

' EDWIN G. LITTLE. 

